When Erin's daughter Maya was six years old, she was diagnosed with schizophrenia. According to Erin, Maya had "good days" and "bad days;" in her worst episodes, she became distressed and irrational, often harassing her neighbor's young son Evan.

At the start of Day 4, Chloe O'Brian received a tip from former classmate Andrew Paige, who told her that some key Internet nodes had been compromised by a virus in a language he thought might be Turkish. Despite knowing that Tomas Sherek, mastermind of the train bombing earlier that morning, was Turkish, Erin ordered Chloe to follow leads pertaining directly to his whereabouts instead.

Erin was to meet with a representative from the Department of Defense to discuss budget allocations, and was surprised to find that the representative was Jack Bauer. The meeting was cut short when Director of Field OperationsRonnie Lobell reached the location where Sherek was hiding out, and Erin was needed to oversee the operation. Jack also observed the sting, and helped by tipping Ronnie off to the clues that Sherek was, in fact, in the building. Ronnie successfully apprehended Sherek and brought him back to CTU. Erin thanked Jack and apologized for being abrupt earlier.

Erin Driscoll

However, Jack was convinced that Sherek was too important to waste his time on a simple train bombing, and told Erin that he must be hiding something. Erin decided to continue with a standard interrogation. Frustrated with the lack of progress and convinced that Chloe was onto something, Jack entered the holding room and shot Sherek in the leg. Sherek confessed that the real target was Secretary of DefenseJames Heller and that the bombing was, as Jack thought, just a diversion.

After Secretary Heller was kidnapped, Jack demanded to be included in the investigation. Still bristling at his earlier illegal and unauthorized shooting of Sherek, Erin refused. Jack told her that if she did not let him in, he would tell her superiors that he was the one who managed to get the information out of Sherek, after her methods failed. She relented, but then had to face down Ronnie Lobell, who thought she had made the wrong decision letting Jack back in the field.

Ronnie and Jack clashed on how to deal with Kalil Hasan, with Ronnie wanting to apprehend and interrogate him, and Jack wanting to follow him and hope he was going to see Secretary Heller. Their argument ended with Hasan shooting Ronnie to death. After hearing what happened, Erin ordered Jack to apprehend Hasan, but Jack refused and hung up. Driscoll ordered all departments to work on locating and apprehending both Jack and Hasan.

Later, Marianne Taylor contacted Erin and told her that Curtis Manning had leaked classified information to her. Regardless of the source of the information, Marianne could use it to mire CTU in security investigations. Not wanting to cripple CTU in a crisis, Erin decided to call her in. Curtis told her that he was uncomfortable working with Marianne, but Erin told him to "deal with it."

Believing Secretary Heller's son Richard to be holding out on some possibly critical piece of information, Erin ordered Curtis to torture him. However, Curtis refused her order and suggested sensory disorientation instead. She agreed to let him try it, but it was no more successful than regular questioning.

After Jack and Chloe rescued Andrew Paige from Kalil Hasan, Erin briefed her department heads on the situation, watching Chloe's reactions. Determining that Chloe knew about Paige and had therefore been in contact with Jack, Erin ordered Sarah Gavin to watch Chloe's computer from her own, and take any other steps necessary to find out how Chloe kept in contact with Jack.

Erin received a phone call from her schizophrenic daughter, Maya, asking her to come home. Erin explained that she was very busy, but promised to come home as soon as she could. Later, her neighbor George Kliavkoff told her that he had called the police after finding Maya screaming at his son again. Erin asked Sarah to call the LAPD and use CTU's preemptive authority to call the cops off. She also had Sarah send a CTU unit with one medic and one field agent to bring Maya to the CTU medical clinic.

Following a tip from the DoD, Curtis found that Chloe had been tracking Jack using a DoD satellite. Erin had Chloe arrested and taken into holding. She called Jack and informed him that CTU would be apprehending Kalil Hasan. Watching Hasan steal a car and cell phone over the satellite, Driscoll had Sarah intercept the phone's next call. Finding that Jack was right about Hasan planning to travel to the site where Secretary Heller was being held, Driscoll ordered the CTU field teams on their way to apprehend Hasan to track him instead.

With no one else available to run the ground operations, Erin gave Jack an official clearance. He asked her to reactivate Chloe, but she refused, instead offering to let Chloe resign, no strings (or indictments) attached. Chloe agreed and left the premises.

When Jack found Secretary Heller's location, Erin ordered him to stand down because the Marines wouldn't be able to get there in time to back him up. Instead, PresidentJohn Keeler had decided to strike the warehouse and kill Heller to spare the public the trauma of seeing him killed by terrorists on U.S Soil. Jack informed Erin of his intention to go in alone to rescue Heller, and she called Keeler to ask him to hold off the missile strike as long as possible. After the successful rescue mission, Erin hired Jack as interim Director of Field Ops, telling him she could use his help as long as the crisis was ongoing.

Maya continued to be disruptive in the CTU clinic, and Erin had to check on her several times. Asked by Dr. Mark Kaylis to sign release forms, Erin realized they had given Maya Haldol, to which the girl was allergic. As the doctors rushed to reverse their mistake, Erin continued to give orders to Sarah Gavin.

Jack and Secretary Heller developed a plan to identify a mole in CTU, feeding Erin wrong information as bait. When the trap implicated Sarah, Erin ordered her arrest and torture, interrogating her personally. She was not entirely convinced that Sarah was a spy, but relented under Secretary Heller's assurances. Later, when it turned out that Marianne Taylor was the mole, Curtis accused Erin of ignoring his advice in hiring her. She pointed out that he had not told her that Marianne was untrustworthy, only that he was uncomfortable working with her. They agreed to cover each other when Division asked about the security breach, and she allowed him to modify certain files to cover both of them.

On the advice of Jack and Secretary Heller, Erin reinstated Tony Almeida at CTU. However, she asked Sarah to spy on him. In return, Sarah demanded that Erin expunge the record of her arrest and give her a promotion with an increase of two pay grades. Erin agreed.

Although Edgar Stiles managed to prevent most of the country's 104 nuclear power plants from melting down, several were still under the control of the terrorists. Edgar almost left to personally try and save his mother, who was threatened by the imminent meltdown of the San Gabriel Island reactor, but Erin convinced him to stay and help. After Curtis Manning found the Dobson Override, Edgar managed to stop the remaining power plants from meltdown and resolve the crisis. Although Maya was still demanding her attention in the clinic, Erin continued to lead CTU on the floor due to the importance of the situation.

Erin cries for Maya

Once all of the nuclear reactors were under control, Erin returned to the clinic, only to find that Maya had committed suicide. Crying, Erin knelt down next to her daughter while all of the medical staff looked on.

After Maya's suicide, Erin insisted to Secretary Heller that she would be able to do her job until the threat subsided; however, she remained distracted and distant. Sarah tried to have her removed from her position, but Tony told her that they did not have time to find a replacement. After nearly fainting, Secretary Heller convinced Erin that it would be a good idea to go home and get some rest. He embraced her and she tearfully agreed, leaving command to Tony Almeida.